Pump

ABSTRACT

A reciprocating fluid operated diaphragm-type pump has a control valve automatically movable at each end of the reciprocating stroke of the pump between two alternate positions to reverse fluid flow to the pump, and thereby cause the pump to reciprocate. A connecting member between the diaphragms of the pump passes through a passage in the control valve and has sealing members located to alternately seal and exhaust the opposite ends of the control valve to pressurized fluid flowing out of the valve passage to the ends of the valve, so that control valve movement at the ends of the pump stroke is positive and rapid.

United States Patent Loeffler et al.

[451 Mar. 28, 1972 54] PUMP [72] inventors: Herbert H. Loeifler,Arlington; Sebastian B. Di Mauro, Maiden, both of Mass.

[73] Assignee: Amicon Corporation, Lexington, Mass.

[22] Filed: Oct. 29, 1970 [2]] Appl. No.: 85,077

Primary Examiner-Robert M. Walker Attorney-R. W. Furlong [57] ABSTRACT Areciprocating fluid operated diaphragm-type pump has a control valveautomatically movable at each end of the reciprocating stroke of thepump between two alternate positions to reverse fluid flow to the pump,and thereby cause the pump to reciprocate. A connecting member betweenthe diaphragms of the pump passes through a passage in the control valveand has sealing members located to alternately seal and exhaust theopposite ends of the control valve to pressurized fluid flowing out ofthe valve passage to the ends of the valve, so that control valvemovement at the ends of the pump stroke is positive and rapid.

12 Claims, 5 Drawing Figures PATENTED MAR 28 1972 SHEET 1 BF 3 FIG IPATENTEDMAR28 I972 3,652,187

sum 2 0F 3 FIG 2 PUMP This invention relates to pumps.

Conventional fluid operated reciprocating pumps usually containself-acting control valves, which are actuated by the moving pumpingmeans (e.g., a piston or a diaphragm) of the pump, or some structureresponsive to movement of the pumping means, at each end of the pumpstroke, to reverse the flow of motive fluid (as air or hydraulic fluid)to the pumping means. The movement of the pumping means to one end ofits stroke, e.g., causes some fluid passage in communication with thecontrol valve to be opened or closed so as to direct or exhaust fluidthrough a part of the control valve, and thus causes the control valveto shift positions so as thereby to change the direction of fluid flowto the pumping means. However, once this valve is moved sufflciently toreverse the flow of fluid, it often happens that this reversal causesthe fluid passage to be again closed or opened before the control valvehas gone entirely to its opposite position. Thus, part of the movementof the control valve is due to the momentum of its initial movement. Ifthe pump malfunctions, or if it is simply shut off during the period oftime when the control valve is moving under momentum, it is possiblethat the control valve can stop intermediate of its two positions. Thus,when the pump is to be started again, it will be necessary to somehowgain access to the control valve or to employ some auxiliary start-upmeans so as to move the control valve to one of its two positions sothat the self-acting pumping may occur and reciprocation can beinitiated.

It is an object of this invention to provide a pump in which the controlvalve is positively impelled between its two reciprocating positions, sothat the pump cannot stall.

Another object is to provide an improved reciprocating diaphragm typepump which is compact, light-weight non corrodible, easy to assemble andmaintain, and of simple, reliable construction.

The invention features a pump comprising an inlet for a motive fluidsupply, such as a source of compressed air, a housing divided into twoseparate compartments, and a pumping member such as a flexible diaphragmspanning and dividing each of these compartments into inner and outerchambers. The material to be pumped enters and exits the outer chambersthrough appropriate material inlet means and outlet means. A connectingmember secures the two pumping members together for simultaneousmovement in like direction, each pumping member being so located in itscompartment that it alternately increases and decreases the size of theouter chamber in relation to the inner chamber, by virtue of theintroduction of motive fluid to the inner chambers, expelling fluid fromthe outer chambers while decreasing the size of that chamber, and takingfluid into the outer chamber when travelling in the opposite directionso as to increase the size of the outer chamber. A valve assembly islocated between the two compartments and comprises a valve chamber whichhas a port in communication with each of the inner chambers, a motivefluid inlet port in communication with the motive fluid supply, at leastone exhaust port, a control valve, and a pair of spaced apart valveseats. The control valve has opposed actuating ends located opposite therespective valve seats, an internal fluid passage between its ends, anda motive fluid inlet to this internal fluid passage. The valve isdisposed to be movable in the valve chamber between two positions, inwhich one or the other of the actuating ends rests on the respective oneor the other of the valve seats, the valve being constructed to connectone of the inner compartments to the fluid inlet port of the valvechamber and the other of the inner compartments to an exhaust inaccordance with its position.

To produce automatic movement of the control valve between its positionsat each extreme of the reciprocating stroke of the connecting member andits associated pumping members, the connecting member is arranged toextend through the aforesaid internal valve passage between theactuating ends of the valve. Two spaced apart sealing members, mountedfor movement with the connecting member, are

sized to form sliding seals in the internal valve passage, one memberbeing disposed on each side of the motive fluid inlet to the valvepassage to prevent motive fluid from passing out of the valve passage tothe respective end of the valve. How ever, when the connecting memberreaches the alternate extreme of its stroke, alternate ones of sealingmembers are carried out of the internal valve passage, to admit motivefluid out of the internal valve passage past one or the other of the actuating ends of the valve, between that end and its'seat. Additionalsealing means, also moving with the connecting member, seal that endfrom exhaust while opening the opposite end to exhaust. The valve thusis moved to its other position. Positive, as well as rapid movement ofthe control valve between these two positions is assured because as soonas the sealing member moves out of the valve passage to admit fluid, thevalve immediately moves in the opposite direction, thus increasing theavailable area for further motive fluid flow from the valve passage tothe actuating end. Since there is increasingly more room for motivefluid to be admitted, the valve movement is continuously accelerated.Moreover, this rapid movement means that the fluid flow area will remainopen to the motive fluid from the internal valve passage until the valvehas reached its other position, since the sealing member, the movementof which has also been reversed, will be unable to catch up to thevalve. Thus, the valve cannot stop between the opposite ends of itscycle, and the pump will be always ready for immediate start-up.

In a preferred valve construction, the internal valve passage of thevalve is of cylindrical shape, the sealing members are secured to theconnecting member, and the connecting member has a portion between thesealing members of smaller cross-sectional area than that of theinternal valve passage so asto provide an annular pressure regiontherebetween, to which the ends of the valve are alternately exposed.

To provide exhaust from the two actuating ends of the valve, a preferredpump includes a partition between each compartment and the valveassembly, an exhaust passage in each partition, concentric with theinternal valve passage so as to allow the connecting member to extendthrough the partitions, and an exhaust port in each passage. The surfaceat the interior end of each passage defines one of the valve seats. Theconnecting member is sized to allow fluid flow between the actuatingends of the valve and the respective exhaust passage, and the aforesaidsealing means are located to prevent such flow. Preferred sealing meanscomprise two additional spaced apart sealing members secured to theconnecting member for movement with it, and sized to form sliding sealsin the exhaust passages. The sealing members are so located that one ofthem is disposed in the respective one of the exhaust passages, sealingthe actuating end of the valve from the exhaust port at certainintervals during the stroke at the connecting member, such as when themember is at the extremes of its stroke so that motive fluid is beingintroduced into the opposite actuating end. The operation of thisembodiment is further facilitated by locating these exhaust sealingmembers in such a manner that even before motive fluid is admitted fromthe internal valve passage to one end of the valve, the opposite end ofthe valve is already opened to exhaust and thus, in a sense, the valveis primed for movement between its positions. In addition, the preferredpump construction has baffle means, constructed, e.g., of a syntheticcellular or foam material, located between the exhaust outlet andatmosphere to reduce noise caused by the very rapid reciprocation of thecontrol valve.

In a preferred valve assembly, the valve chamber has two exhaust ports,one for each of the inner chambers. The control valve has an outersurface comprising axially spaced peripheral seals which definetherebetween three axially spaced annular fluid flow spaces. The twoopposite end spaces are continually in communication with the exhaustports whereas the intermediate space is continually in communicationwith the motive fluid inlet port. Then, at each alternate position ofthe control valve, one of its end spaces is closed to one of the innerchambers, the intermediate space is open to that inner chamber to admitmotive fluid to it, and the other end space is open to the other innerchamber so as to exhaust it.

A preferred pumping member is a flexible diaphragm, which spans itscompartment, and which may be reinforced by rigid plates located on eachside of the diaphragm and connected to each end by a rigid connectingrod. The diaphragm compartments are preferably in the form of opposedouter and inner frustro-conical shapes joined at a common base. Thematerial inlet means to such a compartment is preferably through aninlet conduit disposed radially into the outer frustro-conical shapealong its truncated apical end wall and the material outlet means fromsaid compartment is of similar construction. The material inlet means(or outlet means) also includes a single tubular material passage whichhas an inlet (or outlet) intermediate of its ends, and each of its endsarranged to communicate, past a one-way valve means, with one of theinlet (or outlet) conduits to the diaphragm compartments, so that asingle inlet simultaneously feeds fluid under a unitary pressure to bothcompartments.

Other objects, features, and advantages will be apparent to one skilledin the art from the following description of a preferred embodiment ofthis invention, taken together with the attached drawings thereof, inwhich:

FIG. I is a sectional view of a preferred embodiment of a diaphragm pumptaken along the line 1-1 of FIG. 2;

FIG. 2 is another sectional view of this pump, substantiallyperpendicular to that of FIG. 1 and along the line 22 of FIG.

FIG. 3 is another sectional view of this pump, along the line 3--3 ofFIG. 1, showing in particular the interior construction of a diaphragmcompartment; and,

FIGS. 4 and 5 are enlarged views of the valve assembly of FIG. 1, withthe control valve and connecting rod shown in different positions fromthat of FIG. 1.

The figures show a diaphragm pump '10 including a pump housing 12substantially enclosing a first diaphragm compartment 18, a seconddiaphragm compartment 20, and a valve compartment 22. Pump housing 12comprises a pair of spaced apart identical cylindrical end plates 24,26, a pair of identical opposed inner plates 32, 34, and an annularspacing ring 35. All of the plates and rings are secured together by sixspaced studs 37, extending through appropriate aligned openings in theplates 24, 32, 34, 26 and in spacing ring 35, and held at one end bynuts 40 and washers 41, and at the other end by acorn nuts 44 andretainers 45.

Referring to FIGS. 1 and 3, the first diaphragm compartment 18 is formedbetween a first frustro-conical shape 48 formed in cylindrical plate 24,joined at a common base to an opposed frustro-conical shape 50, formedin inner plate 32. Two tubular counterbores 52 extend radially into thetruncated apical end wall of shape 48, are sealed at their two ends byappropriate plugs 54, and define, with perpendicularly disposed passages57, 58, a material inlet conduit 59 to diaphragm compartment 18 and amaterial outlet conduit 60 from that compartment. A cylindricalcounterbore 62, centrally located in the shape 48 of inner plate 24, issized to receive a nut 64 and the protruding threaded end 65 ofconnecting rod 67.

A flexible diaphragm 68 is secured between the opposed faces of plates24 and 32 around its entire periphery, to divide the compartment 18 intoan outer or pumping chamber 70 in communication with inlet conduit 59and outlet conduit 60, and an inner or motive chamber 72, sealed fromthose passages by the diaphragm 68, and in communication, through atubular inlet 74 formed in plate 32, with the valve compartment 22.Diaphragm 68 may be formed of, e.g., various reinforced elastomers suchas nylon-inserted Buna N, silicon rubber, or fluorocarbons such as thosesold under the trade names VITON, "Kel-F" and the like, or otherflexible materials such as thin, convoluted stainless steel sheet.Diaphragm 68 has a central aperture, through which extends one end ofconnecting rod 67, and disc-shaped diaphragm reinforcing plates 75are'secured on each side of diaphragm 68 between the shoulder 76 of rod67 and the nut 64, with a gasket 78 arranged to provide a fluid-tightseal between the pumping chamber 70 and the motive chamber 72.

A material inlet 80 communicates with the opening 81 into the tubularpassage 82. A spring-biased ball valve 84 is arranged in the ball valvechamber 83 with the shoulder 85 provided at the end of passage 82forming a valve seat for ball valve 84. This ball valve is arranged topass material from inlet 80 and passage 82 to diaphragm pumping chamber70. 'A gasket 88 seals the interface of inner plate 32 and spacing ring35 at valve chamber 83. A material outlet 90 communicates with thetubular passage 92. A spring biased ball valve 94 is arranged in theball valve chamber 93, with the shoulder 95 provided at the end oftubular passage 58 forming a valve seat for ball valve 94. This ballvalve 94 is arranged to pass material from diaphragm pumping chamber 70to outlet 90. A gasket 98 seals the interface of inner plate 32 andspacing ring 35 at valve chamber 93. The diaphragm 68 has an openingadjacent and concentric with each valve chamber 83, 93.

The second diaphragm compartment 20 is formed of frustro-conical shapes148 and 150, identical to the shapes 48, 50 of first diaphragmcompartment 18, and includes two-tubular counterbores 152 extendingradially into shape 148, sealed at their two ends by plugs 154, anddefining, with perpendicularly disposed passages 157, 158, a materialinlet conduit 159 to compartment 20, and a material outlet conduit 160from the compartment 20. Cylindrical counterbore I62, identical tocounterbore 62, is for receiving a nut 164 and opposite threaded end 165of connecting rod 67. A flexible diaphragm 168 (formed of materials suchas previously described for diaphragm 68) is secured between the opposedfaces of plates 26 and 34, around its entire periphery, to divide thecompartment 20 into an outer or pumping chamber 170 in communicationwith inlet conduit 159 and outlet conduit 160, and an inner or motivechamber 172, sealed from those passages by diaphragm 168, and incommunication, through tubular inlet 174, with the valve compartment 22.Disc-shaped diaphragm reinforcing plates 175, which are secured betweenrod shoulder 176 and nut 164, and gaskets 178 are arranged as previouslydescribed for plates 75 and O-rings 78. A cylindrical ball valve chamber183 is formed in inner plate 34 adjacent the tubular passage 82. Aspring-biased ball valve 184 is arranged in chamber 183, with theshoulder 185 provided at the end of passage 82 forming a valve seat forball valve 184. Ball valve 184, like valve 84, passes material frominlet 80 to diaphragm pumping chamber 170. A gasket 188 seals theinterface of inner plate 34 with spacing ring 35 at valve chamber 183. Aspring-biased ball valve 194 is arranged in the ball valve chamber 193,with the shoulder 195 provided at the inner end of tubular passage 158,forming a valve seat for ball valve 194. This ball valve 194 passesmaterial from diaphragm pumping chamber 170 to outlet 90. A gasket 198seals the interface of inner plate 34 with spacing ring 35 at valvechamber 193. The diaphragm 168 has an opening adjacent and concentricwith each valve chamber 183, 193.

Referring now to FIGS. 1 and 4, valve assembly 200 includes a stationaryannular valve housing 202, secured by fasteners 203 between opposedshallow cylindrical detents 205, 206, formed in the opposing surfaces ofinner plates 32, 34. Spool valve 208 has four annular lands 209 eachhaving an annular rubbery O-ring seal 210 at its outer surface,slidingly engaging the inner cylindrical valve chamber 211 of housing202, the seals 210 being located so as to maintain, by friction withchamber 211, the spool valve 208 in position, in the absence of otherforces acting on the spool valve. The seals 210 are fluid-tight anddefine therebetween three annular fluid flow spaces 212, 213, 214 withchamber 211. The entire spool valve, exclusive of seals 210 may beformed of a rigid plastic, such as acetal. Spool valve 208 also hasopposed actuating faces 216, 217 at its opposite ends, disposed oppositethe valve seats 218, 219 formed in inner plates 32, 34, respectively.Spool valve 208 has a central bore defining an internal valve passage220 within which is slidingly received the rubbery O-ring sealingmembers 222, 223, 224, 225 located on connecting rod 67. These sealingmembers provide fluid-tight sliding seals around the connecting rod 67,which has, disposed within the valve passage 220, upper and lowerportions 228, 230 and a reduced diameter central portion 232. Theconnecting rod 67 also extends slidingly through exhaust passages 233,234 in inner plates 32, 34, respectively, and is sealed from thediaphragm compartments 18, 20, by gaskets 236, 237, respectively.

Referring also to FIG. 2, valve housing 202 has an inlet passage 240 incommunication with valve space 213 and also with a compressed airline242, providing a motive fluid supply to operate the pump, and which inturn extends through an opening 244 in spacing ring 35. An annularexhaust port 246 is located between the opening 244 and air line 242,and in communication with the exhaust space 247 in valve compartment 22.An annular air-permeable foam packing ring 248 is arranged as a bafileinterior of and adjacent opening 244, to reduce any noise caused byoperation of the spool valve 208.

Two outer exhaust passages 250, 251 extend between valve chamber 211 andexhaust space 247, are in communication with valve spaces 212, 214,respectively, and also communicate with valve exhaust passages 252, 253,respectively, which in turn communicate, through diagonal passages 254,255, respectively, formed in inner plates 32, 34, respectively, withexhaust passages 233, 234, respectively. The diagonal passages 254, 255are sealed from motive chambers 72, 172, respectively, by connecting rodportion 228 and gasket 236, and connecting rod portion 230 and gasket237, respectively. Inner chamber fluid passages 258, 259, sealed to havea rightangle configuration by sealing fasteners 260, 261, respectively,communicate through passages 74, 174, respectively, with motive fluiddiaphragm chambers 72, 172, respectively.

Inlet 240 is also in communication, through the valve space 213, withone of the inner chamber passages 258, 259, depending on the position ofthe spool valve 208. The other inner chamber inlet passage is incommunication, through valve space 212 or 214, with outer exhaustpassage 250 or 251, respectively, Inlet 240 is also in communication,through narrow radial inlet passages 272, 273 through spool valve 208,with the annular pressure region 274 between the central portion 232 ofconnecting rod 67 and the internal valve passage 220 of spool valve 208.

In operation, a motive fluid, such as compressed air, is introducedthrough inlet line 242 and passage 240 to valve space 213. In theposition of spool valve 218 shown in FIG. 1, this valve space is open,through passages 259, 174 to second diaphragm inner chamber 172.Although both valve spaces 212, 214 are open to atmosphere throughpassages 250, 251, respectively, only valve space 212 is open to innerdiaphragm chamber 72 through passages 258 and 74. Valve space 214 isclosed to inner chamber 172. In this spool valve position, therefore,air under pressure is being introduced into motive chamber 172 and airis being exhausted from chamber 72, causing the diaphragms 68, 168 totravel, in unison by virtue of connecting rod 67, in the downwarddirection in FIG. 1, tending to decrease the size of the inner chamber72 of the first diaphragm compartment 18, and increase the size of theinner chamber 172 of the second diaphragm compartment 20.

The material being pumped, in the meanwhile, is introduced, underpressure, through inlet 80 into passage 82. So long as the fluidpressure in expanding pumping chamber 70 of the first diaphragmcompartment 18 is insufficient, together with the biasing spring of ballvalve 84, to overcome the pressure of incoming material in passage 82,ball valve 84 will be unseated, allowing material to pass into pumpingchamber 70. However, since pumping chamber 170 of the second diaphragmcompartment 20 is decreasing in size with the movement of the diaphragmsindicated in FIG. 1, the combined pressure in chamber 170 and the forceof the biasing spring of ball valve 184, will be sufficient to retainball valve 184 seated, and hence no material will enter chamber 170. Theincreasing pressure in contracting pumping chamber 170 will also unseatball valve 194, so that material may exit through passage 92 and outlet90, whereas the pressure in expanding pumping chamber 70 will beinsufficient to unseat ball valve 94. The one-way orientation of valveseats for the ball valves 84, 184, 94 and 194 prevents backflow ofmaterial through the pump.

In the position shown in FIG. 1, the diaphragms 68, 168 and connectingrod 67 have nearly reached one extreme of the stroke, with pumpingchamber 70 almost filled and pumping chamber 170 almost emptied. Theouter diaphragm pad 174 is close to the apical wall of shape 148, andthe nut 164 and rod end 165 have begun to enter the counterbore 162. Themotive fluid main flow around and within flow spool valve 208 is asfollows. Compressed air from passage 240 is being led continuouslythrough passages 272, 273 to the pressure region 274, but sealingmembers 222, 223 are still preventing air from passing to the actuatingfaces 216 or 217 of valve 208. Diagonal passage 254 is open, however,through the narrow annular space between the upper portion 228 ofconnecting rod 67 and the exhaust passage 233, to the valve chamberspace adjacent actuating face 216, allowing air in that space to exhaustthrough passages 254, 252 and 250. Diagonal passage 255, however, issealed from the valve chamber space adjacent actuating face 217 andhence from the valve spool itself by sealing member 224, which isdisposed within exhaust passage 234.

With slight further movement of the diaphragms and connecting rod in thedownward direction, the sealing member 224 will be moved all the way outof internal valve passage 220, to open the valve chamber adjacent valveactuating face 217 to compressed air from pressure region 274. The valvechamber adjacent opposite actuating face 216 being open to atmosphere,the sudden onrush of compressed air adjacent valve face 217 will liftthe spool valve 208 off valve seat 219. As the spool valve 208 islifted, the annular area for air flow from space 274 between the valve208 and the sealing member 224 rapidly increases in size, acceleratingspool valve movement until the spool valve 208 has travelled to theopposite end of the valve chamber 214, actuating face 216 resting onvalve seat 218, in the position shown in FIG. 4. The valve space 213 hasnow been shifted so as to be between air inlet passage 240 and diaphragmcompartment passage 258 to direct compressed air to motive chamber 72,whereas valve space 214 is located to exhaust air from motive chamber172 through passage 259, space 214, and passage 251. Thus, the rod 67and hence diaphragms 68, 168 connected thereto, will begin to move inthe upward direction, material being expelled from pumping chamber 70past ball valve 94 and through outlet 90, and material being introducedinto expanding pumping chamber 170 through inlet 80, past ball valve184. Long before rod 67 moves sufficiently for sealing member 224 toreseal pressure region 274 from the actuating face 217, the spool valve208 has gone completely to the position shown in FIG. 4. Thus, theentire spool valve movement is under the constant force of compressedair from the source 242, causing a rapid and positive movement of thevalve, and making it impossible for the spool valve to stop in anyposition intermediate of those shown in FIGS. 1 and 4. The pump isalways, therefore, ready for use. Even when compressed air is exhaustedfrom below the valve face 217, frictional forces between the sealingmembers and the wall of valve chamber 211 maintain the valve on one orthe other of its valve seats.

As the connecting rod 67, with movement of the diaphragms undercompressed air, moves to the position shown in FIG. 5, first sealingmember 224 seals pressure region 274 from valve face 217. Next sealingmember 225 moves out of exhaust passage 234, opening the valve chamberadjacent actuating face 217 to atmosphere through passages 255, 253, and251, as sealing member 222 moves into exhaust passage 232, to closecommunication between the valve chamber adjacent actuating face 216 andatmosphere through passages 254, 252 and 250. In this position, as shownin FIG. 5, both actuating faces 216, 217 are closed to the compressedair in space 274, and face 217 is already exposed to atmosphere.Finally, as rod 67 is moved to and past essentially the reverse of theposition of FIG. 1, sealing member 223 will move out of internal valvespace 220, exposing valve face 216 to compressed air from pressureregion 274, rapidly returning the spool valve 208 to the FIG. 1position, to commence another stroke. With air now being introduced intomotive chamber 172 and exhausted from chamber 72, the diaphragms 68, 168will travel back in the direction indicated in FIG. 1, and materialbeing expelled from pumping chamber 170 and filling pumping chamber 70,the diaphragms 68, 168 and rod 67 will complete the cycle back to theposition shown in FIG. 1.

Substantially all parts of the pump may be fonned of metal, such asstainless steel, or of light-weight, noncorrodible rigid plasticmaterials, such as acrylics and the like. The diaphragm pads 74, 174,and connecting rod 67, for greater rigidity, are preferably formed of ametal such as stainless steel, which may be coated, if desired, with anoncorrodible coating such as a thin fluorocarbon film.

Other embodiments will occur' to those skilled in the art and are withinthe following claims.

What is claimed is:

1.,A pump comprising v a housing having two separate compartments,

a pumping member spanning and dividing each ofsaid com- I partments intoinner and outer chambers,

material inlet means and outlet means for each said outer chamber, V v

a valve assembly for controlling movement of said pumping members, saidvalve assembly being located between said compartments and comprising avalve chamber including a port in communication with each said innerchamber, a fluid inlet port for a motive fluid supply, at least oneexhaust port, and a pair of spaced apart valve seats, and

a control valve in said valve chamber having opposed actuating ends, aninternal passage between said ends, and a motive fluid inlet to saidinternal passage, said valve being movable in said valve chamber betweentwo positions in which either one or the other of said actuating endsrests on the respective one or the other of said valve seats, saidcontrol valve being constructed to connect one of said innercompartments to said exhaust port through said valve chamber inaccordance with its position,

. a connecting member between said pumping members, joining said pumpingmembers together for simultaneous movement in said compartments in likedirections in a reciprocating stroke, said connecting member extendingthrough said internal valve passage, at least two spaced apart sealingmembers, responsive to movement of said connecting member, sized to formsliding seals in said internal valve passage, one of said members beingdisposed on each side of the said motive fluid inlet to said internalvalve passage, and so located that alternate ones of said sealingmembers are carried out of said internal valve passage when saidconnecting member reaches the alternate extremes of its said stroke soas to admit motive fluid out of said internal valve passage, past therespective end of said open valve, between that end and its seat, and

sealing means responsive to movement 'of said connecting member toalternate extremes of its stroke to seal that end of said control valvefrom exhaust while opening the opposite end of said control valve toexhaust, to allow movement of said control valve between its positionsin response to said admitted motive fluid.

2. The pump of claim 1 wherein said sealing members and said sealingmeans are secured to said connecting member for movement therewith.

3. The pump of claim 2 wherein said internal valve passage is ofcylindrical shape, said connectigfi memberhas a portion between saidsealing members of sm er cross-sectional area than the cross-sectionalarea of said internal valve passage, defining with said valve passage anannular region continually under fluid pressure from said motive fluidinlet, and said sealing members are located to expose the ends of saidcontrol valve to said pressure region.

4. The pump of claim 1 including a partition between each saidcompartment and said valve assembly, each said partition including anexhaust passage having an exhaust port, each said exhaust passage beingarranged concentric with said inter- I nal valve passage, with saidconnecting member extending through said exhaust passage, and

a surface at the interior end of each said passage defining one of saidvalve seats,

said connecting member and said exhaust passages being sized to allowfluid flow between the said actuating ends of the valve and therespective passage, and said sealing means arranged to prevent saidfluid flow.

5. The pump of claim'4 wherein said sealing means com- I prises twoadditional spaced apart sealing members, secured to said connectingmember for movement therewith, sized to form sliding seal in saidexhaust passages, and so located that one of said sealing members isdisposed in the respective one of said exhaust passages between saidexhaust port and the said actuating end of said valve at each extreme ofthe said strokeof said connecting member.

6. The pump of claim 1 wherein said control valve chamber has twoexhaust ports for said inner chambers, and valve has an outer surfacecomprising axially spaced peripheral seals defining therebetween threeaxially spaced annular fluid flow spaces, the opposite end spaces are incommunication with said exhaust ports, the intermediate space is incommunication with the fluid inlet port from said motive fluid supply,and said spaces are mutually arranged with the valve chamber ports tosaid inner chambers so that, at each alternate position of said controlvalve, one of said end spaces is closed to one said inner chamber, theintermediate space is open to that said inner chamber to admit motivefluid to said chamber, and the other of said end spaces is open to theother said inner chamber to exhaust motive fluid from that chamber.

7. The pump of claim 1 including bafi'le means between said exhaust portand atmosphere.

8. The pump of claim 1 wherein each said pumping member comprises aflexible diaphragm spanning its respective said compartment, andcentrally secured to said connecting member.

9. The pump of claim 8 including rigid reinforcing plates secured toeach side of said diaphragm, and wherein said connecting membercomprises a rigid rod extending through said plates. I

10. The pump of claim 9 wherein each said compartment is constructed inthe form of opposed outer and inner frustroconical shapes joined at acommon base.

11. The pump of claim 10 wherein said material inlet means comprises aninlet conduit radially into the outer frustro-conical shape along itstruncated apical end wall, and said material outlet mans comprises anoutlet conduit radially out of said outer frustro-conical shape shapealong its truncated apical end wall.

12. The pump of claim 11 wherein said material inlet means includes asingle tubular material inlet passage having an inlet openingintermediate of its ends, and with each end arranged to communicate,past a one-way valve means, with one of said inlet conduits, and asingle tubular material outlet passage, having an outletopeningintermediate of its ends, and with each end arranged in communication,past a one-way valve means, with one of said outlet conduits.

Patent No.

I Herbert H.

Loeffler Inventor(s) I: is car and line 35, Y "noncor rb dib le TShQlild 'be, hyphenated; 7

Column l,

' Column 5, line M2, after "re sp ecti fvelyv'g'delete the comma andinsert ape-rig Column 7, li ne l7, hj-p'hen a c ed; I Column 7, line 21,"noneo rroiieie'g sh qu la ib e b yhenated;

after 'lsi'ilfi", I iiret bc'dur renee) Column 7, li ne 46 'inserc"fluid inlet port- Column 7,

Columfi 8, line C60,

"at least two'l'speeed S gned and seaLedpt hi s (SEAL) A,tte'st "ROB RQLQ .-EDWAR D M.FLETCHE,,R ,JRIQI 7 f t'ing' Officer

1. A pump comprising a housing having two separate compartments, apumping member spanning and dividing each of said compartments intoinner and outer chambers, material inlet means and outlet means for eachsaid outer chamber, a valve assembly for controlling movement of saidpumping members, said valve assembly being located between saidcompartments and comprising a valve chamber including a port incommunication with each said inner chamber, a fluid inlet port for amotive fluid supply, at least one exhaust port, and a pair of spacedapart valve seats, and a control valve in said valve chamber havingopposed actuating ends, an internal passage between said ends, and amotive fluid inlet to said internal passage, said valve being movable insaid valve chamber between two positions in which either one or theother of said actuating ends rests on the respective one or the other ofsaid valve seats, said control valve being constructed to connect one ofsaid inner compartments to said fluid inlet port and the other of saidinner compartments to said exhaust port through said valve chamber inaccordance with its position, a connecting member between said pumpingmembers, joining said pumping members together for simultaneous movementin said compartments in like directions in a reciprocating stroke, saidconnecting member extending through said internal valve passage, atleast two spaced apart sealing members, responsive to movement of saidconnecting member, sized to form sliding seals in said internal valvepassage, one of said members being disposed on each side of the saidmotive fluid inlet to said internal valve passage, and so located thatalternate ones of said sealing members are carried out of said internalvalve passage when said connecting member reaches the alternate extremesof its said stroke so as to admit motive fluid out of said internalvalve passage, past the respective end of said open valve, between thatend and its seat, and sealing means responsive to movement of saidconnecting member to alternate extremes of its stroke to seal that endof said control valve from exhaust while opening the opposite end ofsaid control valve to exhaust, to allow movement of said control valvebetween its positions in response to said admitted motive fluid.
 2. Thepump of claim 1 wherein said sealing members and said sealing means aresecured to said connecting member for movement therewith.
 3. The pump ofclaim 2 wherein said internal valve passage is of cylindrical shape,said connecting member has a portion between said sealing members ofsmaller cross-sectional area than the cross-sectional area of saidinternal valve passage, defining with said valve passage an annularregion continually under fluid pressure from said motive fluid inlet,and said sealing members are located to expose the ends of said controlvalve to said pressure region.
 4. The pump of claim 1 including apartition between each said compartment and said valve assembly, eachsaid partition including an exhaust passage having an exhaust port, eachsaid exhaust passage being arranged concentric with said internal valvepassage, with said connecting member extending through said exhaustpassage, and a surface at the interior end of each said passage definingone of said valve seats, said connecting member and said exhaustpassages being sized to allow fluid flow between the said actuating endsof the valve and the respective passage, and said sealing means arrangedto prevent said fluid flow.
 5. The pump of claim 4 wherein said sealingmeans comprises two additional spaced apart sealing members, secured tosaid connecting member for movement therewith, sized to form slidingseal in said exhaust passages, and so located that one of said sealingmembers is disposed in the respective one of said exhaust passagesbetween said exhaust port and the said actuating end of said valve ateach extreme of the said stroke of said connecting member.
 6. The pumpof cLaim 1 wherein said control valve chamber has two exhaust ports forsaid inner chambers, and valve has an outer surface comprising axiallyspaced peripheral seals defining therebetween three axially spacedannular fluid flow spaces, the opposite end spaces are in communicationwith said exhaust ports, the intermediate space is in communication withthe fluid inlet port from said motive fluid supply, and said spaces aremutually arranged with the valve chamber ports to said inner chambers sothat, at each alternate position of said control valve, one of said endspaces is closed to one said inner chamber, the intermediate space isopen to that said inner chamber to admit motive fluid to said chamber,and the other of said end spaces is open to the other said inner chamberto exhaust motive fluid from that chamber.
 7. The pump of claim 1including baffle means between said exhaust port and atmosphere.
 8. Thepump of claim 1 wherein each said pumping member comprises a flexiblediaphragm spanning its respective said compartment, and centrallysecured to said connecting member.
 9. The pump of claim 8 includingrigid reinforcing plates secured to each side of said diaphragm, andwherein said connecting member comprises a rigid rod extending throughsaid plates.
 10. The pump of claim 9 wherein each said compartment isconstructed in the form of opposed outer and inner frustro-conicalshapes joined at a common base.
 11. The pump of claim 10 wherein saidmaterial inlet means comprises an inlet conduit radially into the outerfrustro-conical shape along its truncated apical end wall, and saidmaterial outlet means comprises an outlet conduit radially out of saidouter frustro-conical shape along its truncated apical end wall.
 12. Thepump of claim 11 wherein said material inlet means includes a singletubular material inlet passage having an inlet opening intermediate ofits ends, and with each end arranged to communicate, past a one-wayvalve means, with one of said inlet conduits, and a single tubularmaterial outlet passage, having an outlet opening intermediate of itsends, and with each end arranged in communication, past a one-way valvemeans, with one of said outlet conduits.